Semen Analysis and Physiology

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Questions and Answers

What is the primary role of Sertoli cells in semen production?

They produce seminal fluid.

They store sperm until ejaculation.

They propel sperm during ejaculation.

They support and nourish germ cells. (correct)

Which structure is responsible for the majority of seminal fluid production?

Epididymis

Seminal vesicles (correct)

Prostate gland

Bulbourethral glands

What function does fructose serve in semen?

It contributes to the gray appearance of semen.

It neutralizes acidic environments.

It provides energy for sperm motility. (correct)

It enhances sperm storage in the epididymis.

What is the role of the bulbourethral glands in semen?

They provide alkaline mucus to neutralize acidity. Signup and view all the answers

How does the external location of the scrotum affect sperm development?

It maintains a lower temperature optimal for sperm development. Signup and view all the answers

What happens to sperm in the absence of fructose during semen analysis?

They do not display motility. Signup and view all the answers

Which gland aids in propelling sperm through the urethra during ejaculation?

Prostate gland Signup and view all the answers

What percentage of semen volume is contributed by fluid from the prostate gland?

20% to 30% Signup and view all the answers

What is an appropriate action if liquefaction does not occur after 2 hours?

Add alpha-chymotrypsin or bromelain to induce liquefaction Signup and view all the answers

How is sperm concentration determined using a Neubauer chamber?

Count both sides of the hemocytometer and apply dilution Signup and view all the answers

What is the normal volume range for a semen sample?

2 mL to 5 mL Signup and view all the answers

Which sperm motility rating indicates rapid straight line movement?

4.0 Signup and view all the answers

What pH range is considered normal for semen?

7.2 to 8.0 Signup and view all the answers

What is the significant exclusion criterion in sperm count?

Only fully developed sperm are counted Signup and view all the answers

What percentage of the semen fluid volume is contributed by the bulbourethral glands?

5% Signup and view all the answers

Which viscosity rating corresponds to a gel-like consistency?

3 Signup and view all the answers

What is the minimum percentage of motility considered normal after one hour?

50% Signup and view all the answers

Why is it important for semen to be alkaline?

To neutralize vaginal acidity Signup and view all the answers

What is one consequence of not collecting the first ejaculate during sperm collection?

Falsely decreased sperm count Signup and view all the answers

What visual characteristic is considered normal for semen appearance?

Gray white color Signup and view all the answers

What potential risk does all semen specimens carry, necessitating standard precautions during handling?

Potential reservoirs for HIV Signup and view all the answers

What is the normal timeframe for liquefaction of a fresh semen specimen after collection?

30 to 60 minutes Signup and view all the answers

Which of the following conditions can cause yellow discoloration in a semen sample?

Presence of urine Signup and view all the answers

Which parameter is NOT typically reported in a semen analysis?

Color Signup and view all the answers

What percentage of motility is considered normal for sperm?

66% Signup and view all the answers

What is the primary function of the acrosomal cap of the sperm?

Ovum penetration Signup and view all the answers

What is the length of the sperm's flagellum?

45 µm Signup and view all the answers

A deficiency in what substance is indicated by low sperm concentration?

Seminal vesicle fluid Signup and view all the answers

What is considered the normal quantitative level of fructose per ejaculate?

13 µmol Signup and view all the answers

What technique is used to evaluate the vitality of sperm?

Eosin-Nigrosin stain Signup and view all the answers

What gland contributes alkaline mucus to neutralize vaginal acidity?

Bulbourethral glands Signup and view all the answers

If a specimen shows a large proportion of vital but immobile sperm, what condition might this indicate?

Defective flagellum Signup and view all the answers

What is the significance of testing specimens for fructose levels within 2 hours of collection?

It prevents the breakdown of fructose through fructolysis. Signup and view all the answers

Which condition can potentially lead to the formation of antisperm antibodies?

Vasectomy reversal, trauma, and infection. Signup and view all the answers

How is the presence of antisperm antibodies in a female subject primarily detected?

By observing for agglutination after mixing semen with cervical mucosa. Signup and view all the answers

What does a positive Mixed Agglutination Reaction (MAR) test indicate?

The presence of IgG antibodies against sperm. Signup and view all the answers

Which immunological property is a specific advantage of the Immunobead test?

It indicates which area of the sperm antibodies affect. Signup and view all the answers

What constitutes a normal result in the Immunobead test?

Less than 50% of sperm attached to beads. Signup and view all the answers

What does a white blood cell count greater than 1 million WBCs per milliliter indicate?

There is a potential infection in the reproductive system. Signup and view all the answers

In rape cases, which method is utilized to enhance specimens for microscopic examination?

Specimen enhancement with xylene. Signup and view all the answers

Study Notes

Semen Analysis

Semen analysis is vital for assessing fertility, particularly for couples delaying parenthood and those using assisted reproductive technology (ART).
Routine semen analysis is often performed in clinical labs, and abnormal results may lead to further testing in specialized andrology labs to determine suitability for in vitro fertilization (IVF).

Physiology of Semen Production

Testes: Paired glands in the scrotum, crucial for sperm production. Their external location maintains optimal lower temperature for sperm development.
Seminiferous Tubules: Sperm production begins within the seminiferous tubules. Sertoli cells support and nourish germ cells during mitosis and meiosis (spermatogenesis).
Epididymis: Immature sperm complete maturation and develop flagella in the epididymis before storage until ejaculation.
Vas Deferens: Sperm are propelled through the vas deferens to the ejaculatory ducts.
Seminal Vesicles: Produce the majority of seminal fluid (approximately 60-70%). The fluid contains fructose and flavins as a transport medium for the sperm. The fructose provides energy to the sperm.
Prostate Gland: Located below the bladder, surrounds the upper urethra to propel sperm through the urethra via muscular contractions. It also produces acidic fluid (approximately 20-30% of the volume). The acid fluid contains enzymes (acid phosphatase, citric acid, zinc) for coagulation and liquefaction of the semen.
Bulbourethral Glands: Contribute to lubrication and a more alkaline environment (approximately 5% of the volume). The alkaline mucus neutralizes vaginal acidity, aiding sperm motility.
Absence of Fructose: Crucial for proper sperm motility, without it, sperm will not demonstrate motility in the analysis.
Flavin in Semen: Responsible for the gray appearance, and important for assessing the semen.

Semen Production

Semen production starts with the epithelial cells in seminiferous tubules. Nutrients for spermatogenesis supplied by Sertoli cells support and nourish germ cells during spermatogenesis.
Immature sperm enter the epididymis for maturation and development of flagella. Sperm are stored there until ejaculation.
Once ready, sperm are moved through the vas deferens to the ejaculatory ducts.

Specimen Collection

The first ejaculate contains most of the sperm.
Complete collection is vital to avoid falsely decreased sperm count or altered pH.
Uncollected last portion of ejaculate causes falsely increased sperm count and an altered pH.
Collection of 2 or 3 samples (spaced by no less than 7 days or more than 3 weeks) is advised, collected in a warm sterile container (glass or plastic) via masturbation.
Non-lubricated condoms (polyurethane or rubber) can be used if needed.
Specimens should arrive within 1 hour of collection.
The period of sexual abstinence should be recorded.
Standard precautions (as semen is a potential reservoir for HIV) should be observed during handling.

Semen Analysis Parameters

Appearance: Normal-gray-white, translucent, characteristic musty odor. Abnormal - appears almost clear due to low sperm concentration, or increased white turbidity.
Volume: 2ml to 5ml is normal. Decreased volume is associated with infertility.
Viscosity: Droplets that form longer threads than 2 cm indicate abnormal viscosity; Ratings 0 - watery, 4 – gel like.
pH: Prostatic fluid is acidic, seminal vesicle fluid is alkaline. Normal pH range is 7.2-8.0.
Sperm Concentration & Count: Normal range: 20 million/ml to 250 million/ml (Borderline: 10-20 million/ml).
Sperm Motility: Measured with 0–4 grade. 0-no movement, 4-rapid straight line movement.. minimum 50% motility with a rating of 2.0 after 1 hr is considered normal.
Sperm Morphology: Assessing sperm shape and size. Normal parameters include morphology with > 14/ >30% normal forms (strict/routine criteria).
Microscopic Examination: WBCs differentiation from immature sperm. Red discolorations of RBCs present and considered abnormal. Yellow from urine is toxic to sperm.

Liquefaction

Fresh semen should coagulate and liquefy within 30-60 minutes following collection. Failure to liquefy within 60 minutes requires reporting. Examination should be performed after liquefaction has occurred.
Add alpha-chymotrypsin or bromelain to induce liquefaction if necessary, within 2 hours of collection.

Additional Testing for Abnormal Results

Further testing is advised for cases with abnormal semen analysis, including:
- Vitality: Eosin-nigrosin stain used to evaluate the proportion of living sperm.
- Seminal Fructose: Resorcinol test to determine the presence of fructose.
- Antisperm Antibodies (ASA): Used to detect presence of antibodies in male and female subjects through Mixed Agglutination Reaction (MAR) or Immunobead test.
- Microbial Testing: Determining if possible factors are contributing to abnormalities (e.g., Chlamydia trachomatis, Mycoplasma hominis, Ureaplasma urealyticum).
- Rape cases: Detecting seminal fluid using prostatic acid phosphatase or seminal glycoprotein p30 (prostatic specific antigen)

Postvasectomy Semen Analysis

Assess the presence or absence of spermatozoa.
Routinely test at 2-month intervals post-vasectomy for complete sterilization confirmation.
Examine wet and centrifuged specimens.

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Description

This quiz explores the critical aspects of semen analysis and the physiology behind semen production. It delves into the anatomical structures involved and their roles in fertility assessment. Ideal for those studying reproductive biology or related fields.